Sponge (tool)

      A sponge is a tool consisting of porous material used for cleaning impervious surfaces. Sponges are especially good absorbers of water and water-based solutions.

Sponges are commonly made from cellulose wood fibres or foamed plastic polymers. Some natural sponges are still sold for the same purpose, although most natural sponges are now used either as body/facial sponges or as decorating tools for sponge painting.

There are three other categories of available synthetic sponges, low-density polyether (known as the rainbow packs of non-absorbent sponges), PVA (very dense, highly absorbent material with no visible pores) and polyester.

Polyester sponges are also sub-divided into a variety of types, some being reticulated (artificially broken-in) for ease of use. Other types are double-blown polyester, meaning that they have an high water retention ability, approaching or equalling PVA, but with visible pores and more flexibility of applications.

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Harboring bacteria

Especially when allowed to remain wet between uses, sponges can provide a medium for the growth of harmful bacteria or fungi. Some manufacturers treat sponges with anti-microbials to prevent this. To kill the bacteria on a sponge, one may fully soak it in clean water, then microwave it on high for two minutes. Care must be taken to ensure the sponge is wet, or otherwise the sponge will catch fire during microwaving. ^[1]

Tool use by bottlenose dolphins

Use of sponges as a tool has been described in Bottlenose Dolphins in Shark Bay. A dolphin will keep a marine sponge on its rostrum, presumably to protect it when searching for food in the sandy seabed.^[2] The behaviour, known as sponging, has only been observed in this bay, and is almost exclusively shown by females. This is the only known case of tool use in marine mammals besides Sea Otters. A study in 2005 showed that mothers most likely teach the behaviour to their daughters.^[3]

See also

• Sponge rubber ball

References

1. ^ "MSN article. Retrieved on 2007-01-25.
2. ^ Smolker, R.A., et al.. "Sponge-carrying by Indian Ocean bottlenose dolphins: Possible tool-use by a delphinid }".
3. ^ Krutzen M, Mann J, Heithaus MR, Connor RC, Bejder L, Sherwin WB (2005). "Cultural transmission of tool use in bottlenose dolphins". Proceedings of the National Academy of Sciences 102 (25): 8939-8943.