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Why Orange Juice Tastes Bad in the Morning

A useful way to try and explain how taste works
Useful information
Kit List: 

foods needed:
orange juice.
salty corn chips.
concentrated coffee powder.
Lemon Juice.


This is an old experiment that is not currently in use. This experiment also has some important safety issues, so it is critical to read and understand the risk assessment beforehand.

- Probably best to only work with one or two children for this so you can keep an eye on them.

- Ask the child to spread toothpaste around their mouth. Perhaps use the coffee stirrer to give them a bit of toothpaste, and let them use their tongue to smear it all over - make it nice and foamy!

- As soon as they have finish "brushing", give them a sip of orange juice. Ask them to keep the juice at the front of your tongue, where they had the most toothpaste.

- Notice the taste. Ick!!! Not very good!

- Ask them to rinse their mouth out again and repeat "brushing" and tasting with other foods. This time, taste something sweet.

- Where is the sweet flavor? It should either be missing, or very faint.
- Try the same thing with something salty, again brushing first. Again, the salt flavor is weak or missing.

- Then try it with something sour. I used lemon juice. The sour comes through just fine.

What is happening? Toothpaste contains detergent, to make it foam and help it remove food
from your teeth. This detergent coats your taste buds, which blocks the sweet and salty
flavors. Sour and bitter flavors do not seem to be blocked. This is why you get the bad
taste from the orange juice. You are tasting the sour and bitter part, without the sweet

- If got time also go into how smell and sight are needed to "taste" so many different flavours (like chicken flavour, tomato flavour etc.) even though your tongue can only detect four basic sensations(well five if one counts glutamate, but may be good to ignore that for now...)

- Explain how seventy to seventy-five percent of what we perceive as taste actually comes from our sense of smell. When you put food in your mouth, odor molecules from that food travel through the
passage between the nose and mouth to olfactory receptor cells at the top of your nasal cavity, just beneath the brain and behind the bridge of the nose. It's the odor molecules from food that gives most of our taste sensation.

- Talk about how having a cold or a bunged-up nose could mean they can't "taste" food as well.

Risk Assessment
Risk Assessment: 

  • Allergies – children may be allergic to any of the foods
  • Contamination- foods may get contaminated with other products
  • Risk of Spreading Infection
  • Spillage Risk- Liquid may be spilled onto floor and pose a risk
  • Choking Risk – either with foodstuffs or coffee-stirrer
  • Ensure speak to parents before proceeding with experiment about possible risks.
  • Use foodstuffs with low allergen risks.
  • Wipe and disinfect bench before use. Then cover bench with Benchcote.
  • Keep experiment segregated from other experiments.
  • If suspect contamination then dispose of food batch immediately.
  • Use separate cups/ coffee-stirrers/ food portions for each child. Dispose of materials after use.
  • Clear up spills immediately.
  • Only perform experiment on older children.
  • Carry out experiments on small groups (no more than 2-3 children at any one time) and closely monitor them at all times.
  • Call first aider in case of injury
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