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Curious Minds FAQ

If you don't find your question here, or you would like further clarification, please don't hesitate to call us on 01436 670806, we'll do our very best to help you

Can I call into your shop / office / warehouse to purchase goods?

Yes, we'd be delighted to meet you! We have a fabulous shop in Helensburgh, ten miles from Loch Lomond near Glasgow. You are very welcome to pop in and view our range yourself.

Grasshopper Toy Shop

112 West Princes Street


Argyll & Bute

G84 8XD

Tel: 01436 670806

Can I order over the phone?

Yes absolutely, please call +44 (0)1436-670806. We don't have call queues so you should normally get right through, if we have another caller on the line you can leave your number and we'll call you back.

How long have you been around?

  • The shop has been online since 2004.
  • See our About Us page. You'll see that we have substantial backgrounds in science and our previous team even included programmers for institutes such as NASA and for the Hubble Space Telescope.
  • Call us and talk to us.
  • We advertise in Focus, How It Works, and various school publications. Look in W.H Smiths.

How can I make a rainbow/spectrum?

The simplest method is to place a prism in bright sunlight, and twist and turn it to project the spectrum onto a screen (e.g. a wall or ceiling). Ideally you will be in a room, by a window, so that the wall or ceiling isn't directly illuminated by sunlight. However, if you want more control - such as not having to wait for a sunny day - you need to understand the optical process. The light source ideally needs to be narrow in one dimension, and not spreading out. You can achieve this with a lamp, followed by a slit, then a convex lens (or magnifying glass) The narrower the slit the sharper the spectrum, but less bright. Focus an image of the slit on your screen (be it a box, piece of paper, or a wall or ceiling). Then place the prism or diffraction grating in the beam and rotate it (if prism) till you get the best spectrum. Our Rainbow Spectrum kit is ideal for experimenting and learning how to do this.

What's the difference between the various prisms?

The main factors are:

A bigger prism makes the spectrum wider, but not longer.
Prisms typically are equilateral (3 sides and angles are the same) or right-angled (with two 45° angles)
Glass has a higher refractive index than acrylic, which spreads out the colours more and makes the spectrum longer. Unless stated otherwise, our prisms are glass.

One would normally use an equilateral glass prism for colour dispersion (e.g. in spectroscopes) and right-angled for light deviation, e.g. to shorten binoculars. However, the Discovery prism does a very good job of producing a spectrum in bright sunlight, and I haven't been able to tell which one is 'better' for that, though acrylic would be less susceptible to breakage.

Our Rainbow Spectrum kit contains the glass prism and some diffraction grating and a lens, light source, and instructions on how to create spectra in the absence of bright sunlight, which we highly recommend for anyone wanting to gain some insight into the colour composition of light.

Where's my stuff?

On it's way to you!

  • At Christmas or during very bad weather (snow, flood, ...) deliveries might take longer.
  • The 1-2 working days we quote is based on the Royal Mail's guidelines for delivery times. Occasionally they take a little longer.
  • Please check if your local Post Sorting Office is holding it for you. Normally the postie should leave you a note if you didn't answer the door, but occasionally they don't.
  • Please be aware that sometimes credit cards are declined. If you did not receive a confirmation of your order email from us then we probably did not receive your order.

Which chemistry set /microscope / telescope / ... do you recommend?

Throughout our site you'll find pages titled 'About ...'. Visit them for our recommendations!

Where are you? And who are you?

We are located in Helensburgh, near Loch Lomond, Scotland, but we sell world-wide. We are Dr Wendy Hamilton, CEO and the Curious Minds team of enthusiastic science and toy lovers. Anyone of us may answer the phone when you call.

Do you sell wholesale/trade?

Yes we sell wholesale, if you would like to view our wholesale range please email us: Please note, you need to be a registered business and complete our terms and conditions for us to supply you on a wholesale basis. We check all applications and will require trade references and Pro forma payments for the first orders.

Do you sell to schools, colleges & universities?

Yes we sell to schools, colleges, universities & charities and can provide 30 day payment terms and VAT invoices. Please email us:

Please can you send me a catalogue?

Due to the vast number of catalogues that are sent out from companies across the UK and are never even opened before they end up in landfill, we have decided not to offer paper based catalogues . Instead we made the website easy and pleasurable to navigate. We hope you understand our decision, but if you need further help finding a product please call us; behind the website are knowledgeable people working in a UK based shop.

Do you ship outside the UK?

Yes we ship almost everywhere in the world (subject to government restrictions). If our website does not recognise your postcode, please email your full postal address to us: and we'll get a shipping quote to you.

I own an xxx. Please can you tell me its value?

Sadly we are unable to offer valuations for vintage science equipment. There are many factors that affect an item's value such as condition, manufacturer & whether it is functioning. The best way to determine it yourself is to use eBay. Go to the 'Advanced Search', type in what it is, and check the 'Completed listings' box. This will show you what items like yours have sold for, e.g. brass microscope.